JP2008122832A - Antiglare light diffusing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antiglare light diffusing member which can be easily set within desired extent of surface haze and internal haze when used for a display. <P>SOLUTION: The antiglare light diffusing member is equipped with an antiglare layer containing a binder matrix, particles A and particles B and having irregularity at a surface on a transparent base material. Difference between a refractive index of the particle A and a refractive index of the binder matrix is ≤0.02 and difference between a refractive index of the particle B and the refractive index of the binder matrix is within extent between 0.03 and 0.20. Further in the antiglare light diffusing member, mean particle diameter of the particles A is larger than mean film thickness of the antiglare layer and mean particle diameter of the particles B is smaller than the mean film thickness of the antiglare layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an antiglare light diffusing member provided on the surface of a window or a display. In particular, anti-glare light provided on the surface of liquid crystal displays (LCD), CRT displays, organic electroluminescence displays (ELD), plasma displays (PDP), surface electric field displays (SED), field emission displays (FED), etc. The present invention relates to a diffusion member.

A display such as a liquid crystal display, a CRT display, an EL display, and a plasma display has the following problems from the viewpoint of visibility.
・ External light is reflected when viewing.
-The display light from the display causes scintillation on the display surface.
-The visibility is not good due to the glare of the display light coming directly from the display without being diffused.
・ Visibility also deteriorates due to defects such as uneven brightness.
In order to solve such deterioration and deterioration of visibility, it is known to provide an antiglare light diffusing member on the front surface of the display.

For example, the following techniques are known as the antiglare light diffusing member.
-An anti-glare light diffusing member having an anti-glare layer embossed is provided on the surface of the display.
An anti-glare light diffusing member having an anti-glare layer having irregularities formed on the surface by mixing particles in the binder matrix is provided on the surface of the display.
In such an antiglare light diffusing member, a light scattering phenomenon (surface diffusion) due to surface irregularities is used.
Furthermore, an anti-glare light diffusing member that utilizes internal scattering (internal diffusion) of light due to a difference in refractive index between the binder matrix and the particles by mixing particles having a refractive index different from that of the binder matrix is also known. .

The antiglare light diffusing member having irregularities formed on the surface by embossing can completely control the irregularities on the surface. Therefore, reproducibility is good. However, if there is a defect or foreign matter adhesion on the embossing roll, the defect will end up with the roll pitch. Therefore, in the case of mass production, all products are defective. Further, since only scattering on the surface is used, there are the following problems.
・ Abrasion resistance ・ Contrast reduction ・ Glittering

  The antiglare light diffusing member using the binder matrix and particles has fewer steps than the antiglare light diffusing member using the embossing. Therefore, it can be manufactured at low cost. Therefore, antiglare light diffusing members of various modes are known (Patent Document 1).

For example, the following antiglare light diffusing members are known.
It is necessary to improve visibility by preventing the reflection of external light and scintillation. Therefore, the following methods are considered.
・ Improve the light scattering performance by increasing the surface roughness.
-Improve the light scattering performance by increasing the amount of added particles.
However, the above-described method has a problem that transmitted image definition is lowered. The following techniques are known as methods for improving visibility without deteriorating light scattering performance and the like.
・ A technology that uses a binder matrix resin, spherical particles, and amorphous particles in combination (Patent Document 2)
-Technology using binder matrix resin and a plurality of particles having different particle diameters (Patent Document 3)
・ Technology that has surface irregularities and defines the cross-sectional area of the recess (Patent Document 4)

In addition, in order to improve the visibility without deteriorating the light scattering performance or the like, there is also known a technique that uses both scattering inside the antiglare light diffusing member and scattering on the surface of the antiglare light diffusing member. Scattering (internal diffusion) inside the antiglare light diffusing member is caused by dispersing particles having a refractive index different from that of the binder matrix inside the binder matrix such as a resin. In order to exhibit sufficient light diffusion performance, it is necessary to form a certain degree of surface irregularities on the surface of the antiglare light diffusing member. However, there are the following problems.
・ Contrast reduction ・ Glare due to surface unevenness lens effect ・ Scratch resistance reduction When used in combination with internal scattering and surface scattering, surface unevenness compared to anti-glare light diffusing members using only surface scattering Is small. Therefore, there are the following advantages.
-Improvement of contrast-Reduction of glare caused by lens effect of surface irregularities-Improvement of scratch resistance For example, the following techniques are known as techniques for using internal scattering and surface scattering in combination.
-Technology in which the internal haze (cloudiness) is 1 to 15% and the surface haze (cloudiness) is 7 to 30% (Patent Documents 5 and 6)
-Technology using a binder resin and particles having a particle size of 0.5 to 5 μm, and the refractive index difference between the resin and the particles is 0.02 to 0.2 (Patent Document 7)
A technique in which a binder resin and particles having a particle diameter of 1 to 5 μm are used, and the difference in refractive index between the resin and the particles is 0.05 to 0.15. Furthermore, the technique which prescribed | regulated the solvent to be used, surface roughness, etc. (patent document 8, patent document 9, patent document 10, patent document 11, patent document 12)
-Technology that uses a binder resin and a plurality of particles, and the refractive index difference between the resin and the particles is 0.03 to 0.2 (Patent Document 13, Patent Document 14)

  In addition, the following techniques for reducing a decrease in contrast and a change in hue when the viewing angle is changed are also known. In this technique, the surface haze (cloudiness) is 3 or more. Further, the difference between the haze value in the normal direction and the haze value in the ± 60 ° direction is 4 or less. (Patent Literature 15, Patent Literature 16, Patent Literature 17, Patent Literature 18) Further, a technique in which the center line average roughness (Ra) is 0.2 μm or less is also known. (Patent Document 19) A technique in which the center line average roughness (Ra) is 0.02 to 1 μm and the ten-point average roughness (Rz) / Ra is 30 or less is also known. (Patent Literature 20, Patent Literature 21)

Further, since the antiglare light diffusing member is mainly provided on the front surface of the display, scratch resistance is required. In order to improve the scratch resistance, it is necessary to improve the hardness of the antiglare light diffusing member. Therefore, in order to create an antiglare light diffusing member having high hardness without degrading the display image quality of the display, a technique using an ionizing radiation curable resin binder, silica particles, and silicone particles is known. (Patent Document 21)

As described above, antiglare light diffusing members having various configurations for various purposes are disclosed.
The performance required for the antiglare light diffusing member varies depending on the display when used on the front surface of the display. For example, the optimal anti-glare light diffusing member varies depending on the display resolution and intended use. Various anti-glare light diffusing members are required depending on the purpose.

  In general, for an antiglare light diffusing member, physical properties such as a surface haze value mainly indicating the degree of surface diffusion, an internal haze value mainly indicating the degree of internal diffusion, image sharpness, and glossiness are important. In addition, when an antiglare light diffusing member is used on the front surface of a display, physical properties such as hardness are also important. In addition, applicability at production, cost, curl, etc. must be taken into consideration. Therefore, there are many factors such as a film thickness that are limited. It is difficult to control surface haze, internal haze, and the like within a limited range.

  In an antiglare light diffusing member using a binder matrix and one kind of particles, one kind of particles affects surface haze and internal haze. Therefore, it is difficult to set the desired surface haze and internal haze. For example, when the surface haze is lowered without changing the internal haze, it cannot be controlled only by the amount of particles added. That is, it is necessary to redo the design of the type, particle size, addition amount, etc. of the particles to be used from the beginning.

Moreover, even in the following case using a plurality of types of particles, it is difficult to set the desired surface haze and internal haze.
・ When using particles with the same refractive index but different particle size ・ When the refractive index of all particles is somewhat different from the refractive index of the resin

US Pat. No. 5,387,463 JP 2003-260748 A JP 2004-004777 A JP 2003-004903 A Japanese Patent No. 3507719 US Pat. No. 6,343,865 JP 11-326608 A Japanese Patent No. 3515426 US Pat. No. 6,696,140 US Pat. No. 7,033,638 US Patent Application Publication No. 2002/0150722 US Patent Application Publication No. 2004/0150874 Japanese Patent No. 3515401 US Pat. No. 6,217,176 JP-A-11-160505 US Pat. No. 6,111,699 US Pat. No. 6,327,088 US Pat. No. 6,480,249 JP 2003-149413 A JP 2004-125958 A JP 2004-082613 A US Patent Application Publication No. 2004/0071986

  The present invention has been made in view of this problem, and provides an antiglare light diffusing member that can be easily set within a range of desired surface haze and internal haze when used in a display. Objective.

  In order to solve the above-mentioned problems, an invention according to claim 1 is an antiglare light diffusing member comprising an antiglare layer including a binder matrix, particles A and particles B on a transparent substrate and having irregularities on the surface. Thus, the difference between the refractive index of the particle A and the refractive index of the binder matrix is 0.02 or less, and the difference between the refractive index of the particle B and the refractive index of the binder matrix is 0.03 to 0.20. The average particle diameter of the particles A is larger than the average film thickness of the antiglare layer, and the average particle diameter of the particles B is smaller than the average film thickness of the antiglare layer. It was set as the anti-glare light diffusing member.

  The invention according to claim 2 is that the average particle size of the particles A is larger than the average film thickness of the antiglare layer and smaller than a value obtained by multiplying the average film thickness of the antiglare layer by 1.4. The anti-glare light diffusing member according to claim 1 is characterized.

  In the invention according to claim 3, the average particle size of the particles B is smaller than the value obtained by multiplying the average film thickness of the antiglare layer by 0.9, and the average film thickness of the antiglare layer is multiplied by 0.2. The antiglare light diffusing member according to claim 1, wherein the antiglare light diffusing member is larger than the above value.

  In the invention according to claim 4, the content of the particles A with respect to the antiglare layer is in the range of 1.0 to 4.5 wt%, and the content of the particles B with respect to the antiglare layer is 0.5 to 4.5. The anti-glare surname light diffusing member according to claim 1, wherein the content is within a range of 4.0 wt%.

  The invention according to claim 5 provides the antiglare member according to claim 1, wherein the film thickness of the antiglare layer is in the range of 2 to 25 μm.

  The invention according to claim 6 provides the antiglare diffusing member according to claim 1, wherein the standard deviation of the particle size of the particles A is 40% or less of the average particle size.

  The invention according to claim 7 provides the antiglare diffusing member according to claim 1, wherein the standard deviation of the particle size of the particles B is 15% or less of the average particle size.

  The invention according to claim 8 provides the antiglare light diffusing member according to claim 1, wherein the substrate is a triacetyl cellulose film.

  The invention according to claim 9 provides the antiglare light diffusing member according to claim 1, wherein the base material also serves as a polarizing plate.

  The invention according to claim 10 is a transmission type liquid crystal display comprising the antiglare light diffusing member according to claim 1, a polarizing plate, a liquid crystal cell, a polarizing plate, and a backlight unit.

  ADVANTAGE OF THE INVENTION According to this invention, the anti-glare light-diffusion member with favorable visibility which can make external light reflection prevention property and favorable contrast compatible can be obtained easily.

  The antiglare light diffusing member of the present invention will be described.

FIG. 1 shows a schematic cross-sectional view of the antiglare diffusing member of the present invention.
The antiglare light diffusing member (1) of the present invention has an antiglare layer (12) on a transparent substrate (11). The antiglare layer provided on the transparent substrate contains a binder matrix (120), particles A (12A), and particles B (12B). The particles A of the present invention (12A), the having a refractive index and the refractive index of the binder matrix is 0.02 or less, and an average particle size (h _a) the average film thickness of the antiglare layer ( It is characterized by being larger than H). The particle B (12B) of the present invention has a refractive index difference between its refractive index and the binder matrix in the range of 0.03 to 0.20, and its average particle size (h _b ) is the antiglare layer. It is smaller than the average film thickness (H).

  In the present invention, by incorporating the particles A in the antiglare layer, the average particle diameter is larger than the average film thickness of the antiglare layer, so that irregularities are formed on the surface of the antiglare layer. Surface diffusion can be generated for light incident on the surface of the antiglare layer due to the unevenness, and the particles A contribute to the surface diffusion of the antiglare layer. The particle B has a refractive index difference between the refractive index of the particle B and the binder matrix, so that internal diffusion can be generated with respect to the light incident on the antiglare layer, and the particle B is antiglare. Contributes to the internal diffusion of the layer.

  On the other hand, since the refractive index of the particle A is close to the refractive index of the binder matrix, it hardly contributes to the internal diffusion for the light incident on the antiglare layer. Further, in the case of the particle B, since the average particle size is smaller than the average film thickness of the antiglare light diffusing layer, the particle B does not form irregularities on the surface of the antiglare layer, so that the particle B is incident on the surface of the antiglare layer. Hardly contributes to the surface diffusion of the light.

  In the present invention, the particles A and the particles B function separately for the light diffusion performance of the antiglare layer. Therefore, the antiglare light diffusing film of the present invention can easily control glare and contrast.

  The refractive index of the binder matrix of the present invention means the refractive index of the film after the film is formed with the binder matrix.

  In particular, in the present invention, the particle A preferably has an average particle size larger than the average film thickness of the antiglare layer and smaller than a value obtained by multiplying the average film thickness of the antiglare layer by 1.4. More preferably, the average particle diameter of the particles A is larger than the average film thickness of the antiglare layer, and more preferably smaller than a value obtained by multiplying the average film thickness of the antiglare layer by 1.2.

  In the present invention, the particle B has an average particle size smaller than a value obtained by multiplying the average film thickness of the antiglare layer by 0.9 and a value obtained by multiplying the average film thickness of the antiglare layer by 0.2. Larger is preferred. More preferably, the average particle size of the particles B is preferably smaller than a value obtained by multiplying the average film thickness of the antiglare layer by 0.8 and larger than a value obtained by multiplying the average film thickness of the antiglare layer by 0.5. .

  In the present invention, the refractive index difference between the particles B and the binder matrix is 0.03 to 0.20, and more preferably 0.05 to 0.08. When the refractive index difference is 0.03 or less, internal diffusion is insufficient. Further, when the refractive index difference is 0.20 or more, the antiglare layer is easily whitened.

  The refractive index of the particles B is preferably higher in the range of 0.03 to 0.20 than the refractive index of the binder matrix. When the refractive index of the particles is lower than the refractive index of the binder matrix, the light emitted from the inside of the display tends to be totally reflected at the interface between the particles and the binder matrix. As a result, the amount of light on the surface may be reduced.

  In the present invention, the content of the particles A with respect to the antiglare layer is 1.0 to 4.5 wt%, and the content of the particles B with respect to the antiglare layer is within the range of 0.5 to 4.0 wt%. In particular, an antiglare light diffusing member having a low contrast and a high contrast can be obtained. When the content of the particles A is 1 to 4.5 wt% with respect to the antiglare layer and the content of the particles B is 0.5 to 4.0 wt% with respect to the antiglare layer, the particles A Anti-glare light with high contrast that can efficiently diffuse the surface of light incident on the anti-glare layer, and can effectively diffuse the internal diffusion of the light incident on the anti-glare layer. It becomes a diffusion member.

  In the present invention, the average film thickness of the antiglare layer is the average value of the film thickness of the uneven antiglare layer. The average film thickness can be determined by an electronic micrometer or a fully automatic fine shape measuring machine. The refractive index can be obtained by the Becke line detection method (immersion method).

  In the present invention, the value measured by the light scattering method can be used as the average particle diameter of the particles. The light scattering method will be described below. Prepare a sample solution containing the particles. The sample solution is measured with a light scattering particle size distribution measuring apparatus. At this time, the sample solution containing the particles needs to be prepared so that aggregation does not occur, and the sample solution is appropriately diluted with a diluent according to the type of particles.

  Moreover, in this invention, it is preferable that the average film thickness of the said glare-proof layer exists in the range of 2 micrometers-25 micrometers. When the average film thickness of the antiglare layer is less than 3 μm, white blurring may occur. Moreover, when the average film thickness of an anti-glare layer exceeds 12 micrometers, it will become expensive. More preferably, it is 2 μm to 25 μm.

  The surface hardness of the antiglare layer is preferably 3H or more in the pencil hardness defined by JIS K5400. More preferably, it is 4H or more. If the pencil hardness is 3H or higher, more preferably 4H or higher, the antiglare light diffusing member of the present invention can have sufficient scratch resistance when provided on the display surface.

  The antiglare layer of the present invention preferably has a surface haze value of 1 to 7%. And it is preferable that an internal haze value is 1 to 7%. When the surface haze value is 1% or less, the effect of preventing reflection of external light is insufficient. When the surface haze value is 7% or more, contrast becomes a problem. On the other hand, glare is conspicuous when the internal haze value is 1% or less. When the internal haze value is 7% or more, the front luminance decreases. Surface scattering and internal scattering are controlled so that the surface haze value and internal haze value become the above values. Then, the glare-proof layer of this invention can be used for a high-definition display, a display used indoors, in a car, etc. Moreover, the anti-glare layer of this invention can be used for various uses.

  In the antiglare light diffusing member of the present invention, other functional additives may be added to the binder matrix. However, other functional additives should not affect transparency, light diffusibility, etc. As the functional additive, an antistatic agent, an ultraviolet absorber, an infrared absorber, an antifouling agent, a water repellent, a refractive index adjuster, an adhesion improver, a curing agent, and the like can be used. The antiglare layer of the present invention may have functions other than the antiglare function such as an antistatic function, an ultraviolet absorbing function, an infrared absorbing function, an antifouling function, and a water repellent function.

  In addition, the antiglare light diffusing member of the present invention is a functional layer having antireflection performance, antistatic performance, antifouling performance, electromagnetic wave shielding performance, infrared absorption performance, ultraviolet absorption performance, color correction performance, etc., if necessary. Is provided. Examples of these functional layers include an antireflection layer, an antistatic layer, an antifouling layer, an electromagnetic wave shielding layer, an infrared absorption layer, an ultraviolet absorption layer, and a color correction layer. These functional layers may be a single layer or a plurality of layers. The functional layer may have a plurality of functions as a single layer, such as an antireflection layer having antifouling performance. Further, a primer layer, an adhesive layer, or the like may be provided between the respective layers in order to improve the adhesion between the transparent substrate and the antiglare layer, or to improve the adhesion between various layers.

  The cross-sectional schematic diagram of another aspect of the anti-glare light-diffusion member of this invention was shown in FIG. In FIG. 2, the antiglare light diffusing member (1) is provided with an antiglare layer (12) on a transparent substrate (11), and further, an antireflection layer (13) on the antiglare layer (12). Is provided. The antireflection layer (13) may be composed of a single low refractive index layer or may be composed of a plurality of layers obtained by repeating a low refractive index layer and a high refractive index layer.

  The antiglare light diffusing member of the present invention includes various types such as a liquid crystal display (LCD), a CRT display, an organic electroluminescence display (ELD), a plasma display (PDP), a surface electric field display (SED), and a field emission display (FED). It can be applied to the surface that is the viewing side of the display. When used in a display, the antiglare light diffusing member of the present invention provides an antiglare light diffusing member capable of satisfying both external light reflection preventing property and good contrast.

  The cross-sectional schematic diagram of the transmissive liquid crystal display using the anti-glare light diffusing member of the present invention in FIG. 3 is shown. In the transmissive liquid crystal display of FIG. 3A, the backlight unit (5), the polarizing plate (4), the liquid crystal cell (3), the polarizing plate (2), and the antiglare light diffusing member (1) are arranged in this order. I have. At this time, the antiglare light diffusing member (1) side is the observation side, that is, the display surface.

  The backlight unit (5) includes a light source and a light diffusing plate. The liquid crystal cell has a structure in which an electrode is provided on one transparent substrate, an electrode and a color filter are provided on the other transparent substrate, and liquid crystal is sealed between both electrodes. The polarizing plate provided so as to sandwich the liquid crystal cell (3) has a structure in which the polarizing layer (21, 41) is sandwiched between the transparent base materials (21, 22, 41, 42).

  In the transmissive liquid crystal display of FIG. 3B, the backlight unit (5), the polarizing plate (4), the liquid crystal cell (3), the polarizing plate (2) and the antiglare light diffusing member (1) are integrated. The polarizing plate unit (7) is provided in this order.

  The antiglare light diffusing member of the present invention is a liquid crystal display, and the antiglare light diffusing member (1) of the present invention is a transparent substrate provided with an antiglare layer (12) as shown in FIG. The polarizing layer (23) may be provided on the surface opposite to the surface provided with the antiglare layer (12) of (11), and the transparent substrate (11) may also serve as a polarizing plate.

  Next, the manufacturing method of the anti-glare light diffusing member of this invention is demonstrated.

  As the base material used for the antiglare light diffusing member of the present invention, glass, plastic film or the like can be used. The plastic film only needs to have appropriate transparency and mechanical strength. For example, polyethylene terephthalate (PET), triacetyl cellulose (TAC), diacetyl cellulose, acetyl cellulose butyrate, polyethylene naphthalate (PEN), cycloolefin polymer, polyimide, polyethersulfone (PES), polymethyl methacrylate (PMMA), A film such as polycarbonate (PC) can be used.

  In particular, when an antiglare light diffusing member is used on the front surface of a liquid crystal display or the like, triacetyl cellulose (TAC) is preferably used because it has no optical anisotropy. Moreover, it is good also considering a polarizing plate as a base material. The polarizing plate to be used is not particularly limited. For example, what has the stretched polyvinyl alcohol (PVA) which added the iodine as a polarizing layer between a pair of triacetyl cellulose (TAC) films which are a support body of a polarizing layer can be used. A polarizing plate made of stretched PVA added with a TAC film and iodine has a high degree of polarization and can be suitably used for a liquid crystal display or the like. In this case, an antiglare layer can be provided on one triacetyl cellulose (TAC).

  Moreover, in the transparent base material of this invention, it is preferable that thickness of a base material is 10-500 micrometers from viewpoints, such as an optical characteristic, mechanical strength, and handleability.

  Moreover, you may add an additive to a base material. Examples of the additive include an ultraviolet absorber, an infrared absorber, an antistatic agent, a refractive index adjuster, and an enhancer.

The binder matrix used for the antiglare layer is required to have the following characteristics.
-When a film is formed using a binder matrix, the film has appropriate transparency and mechanical strength.
-The added particles are dispersed in the binder matrix.
For example, an inorganic or organic-inorganic composite matrix obtained by hydrolyzing and dehydrating and condensing ionizing radiation curable resins such as ultraviolet curable resins and electron beam curable resins, thermosetting resins, thermoplastic resins, and metal alkoxides. Can be used.

Examples of the thermosetting resin include a thermosetting urethane resin composed of an acrylic polyol and an isocyanate prepolymer, a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, and a silicone resin.

  Examples of the ionizing radiation curable resin include polyfunctional acrylate resins such as polyhydric alcohol acrylic acid or methacrylic ester, diisocyanate, polyhydric alcohol and acrylic acid or methacrylic hydroxy ester. Examples include functional urethane acrylate resins. Besides these, polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can also be used.

  Among the ionizing radiation curable resins, when an ultraviolet curable resin is used, a photopolymerization initiator is added. Although what kind of thing may be used for a photoinitiator, it is preferable to use what was suitable for resin to be used.

  As the photopolymerization initiator (radical polymerization initiator), benzoin such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl methyl ketal, and alkyl ethers thereof are used. The usage-amount of a photosensitizer is 0.5-20 wt% with respect to resin. Preferably it is 1-5 wt%.

  Thermoplastic resins include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose, and methylcellulose, vinyl acetate and copolymers thereof, vinyl chloride and copolymers thereof, vinylidene chloride and copolymers thereof, and the like. Acetal resin such as acryl resin, polyvinyl formal, polyvinyl butyral, acrylic resin and its copolymer, acrylic resin such as methacryl resin and its copolymer, polystyrene resin, polyamide resin, linear polyester resin, polycarbonate resin, etc. are used it can.

  As the inorganic or organic-inorganic composite matrix, a material using a silicon oxide matrix made of a silicon alkoxide material can be used. Specifically, tetraethoxysilane can be exemplified.

  Moreover, when a base material is a plastic film, in order to supplement mechanical strength, it is preferable to use a binder matrix with high hardness. Specifically, an inorganic or organic-inorganic composite matrix obtained by hydrolysis and dehydration condensation of a curable resin or metal alkoxide can be used. In particular, when a plastic film having a film thickness of 100 μm or less is used, it is preferable to use a binder matrix having high hardness.

  In particular, the binder matrix of the antiglare light diffusing member of the present invention is preferably an ionizing radiation curable resin such as an ultraviolet curable resin or an electron beam curable resin. If it is an ionizing radiation curable resin, an antiglare layer having a certain degree of flexibility and having a high hardness such that there is no cracking and the surface hardness exceeds 3H can be produced.

  In the light diffusing member of the present invention, the difference between the refractive index of the binder matrix and the refractive index of the substrate is preferably 0.01 to 0.12. By setting the difference between the refractive index of the binder matrix and the refractive index of the substrate to 0.01 to 0.12, it is possible to suppress the occurrence of haze due to the difference in refractive index between the binder matrix and the substrate. In particular, in the case of an anti-glare light diffusing material consisting only of a base material and an anti-glare layer, the difference between the refractive index of the binder matrix and the refractive index of the transparent base material in terms of Hz generation due to the difference in refractive index between the binder matrix and the base material. Is preferably 0.01 to 0.08. When providing an antireflection layer on the antiglare layer, the difference between the refractive index of the binder matrix and the refractive index of the transparent substrate is preferably 0.03 to 0.12. The refractive index of a triacetyl cellulose (TAC) film that can be used as a transparent substrate is about 1.49. The refractive index of polyethylene terephthalate (PET) film is about 1.68. Therefore, there are many materials whose refractive index is around 1.5 to 1.6. Therefore, the refractive index of the binder matrix is preferably about 1.46 to 1.65.

  Note that, again, the refractive index of the binder matrix of the present invention means the refractive index of the film after the film is formed with the binder matrix. That is, when a curable resin is used, it means the refractive index of the film after it has been cured to form a film. The refractive index of the binder matrix is a value obtained from a binder matrix that does not contain particles for measurement.

  In the present invention, two kinds of particles are included. That is, the antiglare layer of the present invention contains at least particles A and particles B. Particle A is added to impart surface diffusion. Particle B is added to impart internal diffusion. In the present invention, surface diffusion and internal diffusion are imparted by separate particles. Therefore, the surface haze and internal haze caused by surface diffusion and internal diffusion can be easily controlled only by controlling the addition amount of each particle.

  Particles A and B used in the antiglare light diffusing layer of the present invention include acrylic particles (refractive index 1.49), acrylic-styrene particles (refractive index 1.49 to 1.59), talc (refractive index). 1.54), various aluminosilicates (refractive index 1.50-1.60), kaolin clay (refractive index 1.53), MgAl hydrotalcite (refractive index 1.50), styrene particles (refractive index 1. 59), acrylic styrene particles (refractive index 1.58), polycarbonate particles (refractive index 1.58), melamine particles (refractive index 1.66) and the like.

  In the present invention, the particle A has a refractive index difference with the binder matrix of 0.02 or less, and the average particle size needs to be larger than the average film thickness of the antiglare layer. In particular, the average particle diameter of the particles A is preferably larger than the average film thickness of the antiglare layer and smaller than a value obtained by multiplying the antiglare layer by 1.4.

  Further, it is preferable to use particles having a standard deviation of the particle size of the particles A of 40% or less of the average particle size. The standard deviation of the particle size can be calculated from the particle size distribution obtained by volume frequency using the above-mentioned light scattering particle size distribution measuring device.

  Further, the particle B has a refractive index difference from the binder matrix of 0.03 to 0.20, and its average particle size needs to be smaller than the average film thickness of the antiglare layer. In particular, the average particle size of the particles B may be smaller than the value obtained by multiplying the average film thickness of the ghost illusion by 0.9 and larger than the value obtained by multiplying the average film thickness of the antiglare layer by 0.2. preferable.

  The refractive index of the particles B is preferably 0.03 to 0.20 higher than the refractive index of the binder matrix. If the refractive index of the particles is lower than the refractive index of the binder matrix, the light emitted from the inside of the display is likely to be totally reflected at the interface between the particles and the binder matrix, and as a result, the amount of light on the surface may be reduced.

  Further, it is preferable to use particles having a standard deviation of the particle size of the particles B of 15% or less of the average particle size. More preferably, a monodispersed one is used. In the case of monodispersion, it is possible to further reduce the decrease in front luminance.

  Moreover, it is preferable that the shape of the particle A and the particle B is spherical. In particular, when the particle B is spherical, a decrease in front luminance due to internal diffusion of light emitted from the display can be reduced, and a decrease in contrast of the display material can also be reduced. Note that the spherical particles include complete spherical particles and elliptical spheres. Moreover, the particle | grains continuously formed by the spherical surface are also included.

  In the present invention, the content of the particles A with respect to the antiglare layer is 1.0 to 4.5 wt%, and the content of the particles B with respect to the antiglare layer is within the range of 0.5 to 4.0 wt%. It is preferable that the content of the particles A and the particles B with respect to the antiglare layer is within the above range, whereby an antiglare light diffusing member having less contrast and high contrast can be obtained. That is, the particle A efficiently diffuses the surface of the light incident on the anti-glare layer, and the particle B efficiently diffuses the light incident on the anti-glare layer, thereby reducing glare and high contrast. An antiglare light diffusing member can be obtained.

  The antiglare layer is formed by applying a coating liquid containing the raw material of the binder matrix and the particles A and B to the base material. And a glare-proof layer can be obtained on a base material by drying or hardening this coating liquid.

The coating liquid may contain a solvent as necessary.
As the solvent, it is necessary to use a solvent that disperses the raw material of the binder matrix and the particles A and B. Moreover, the solvent needs to have coating suitability. For example, toluene, cyclohexanone, acetone, ketone, ethyl cellosolve, ethyl acetate, butyl acetate, methyl isobutyl ketone, isopropanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, nitromethane, 1,4-dioxane, dioxolane, N-methylpyrrolidone, ethyl acetate, Methyl acetate, butyl acetate, dichloromethane, trichloromethane, trichloroethylene, ethylene chloride, trichloroethane, tetrachloroethane, N, N-dimethylformamide, chloroform and the like can be used, and a mixed solvent thereof can be used. The amount of solvent is not particularly limited.

  At this time, a solvent that dissolves the base material can be used. By using a solvent that dissolves the base material, the adhesion strength between the base material and the antiglare layer interface can be increased. More preferably, a mixed solvent of a solvent that dissolves the base material and a solvent that does not dissolve the base material is used.

  As a coating method, a coating method using a roll coater, a reverse roll coater, a gravure coater, a knife coater, a bar coater, or a slot die coater can be used.

  The solid content concentration of the coating liquid varies depending on the coating method. Solid content concentration should just be about 30 to 70 weight% by weight ratio.

  A case where an antiglare layer is formed using a curable resin as a binder matrix will be described. The aforementioned coating liquid is applied on the substrate. Thereafter, the coating liquid is cured by applying external energy such as ultraviolet rays, electron beams, and heat to the coating liquid. Thus, an antiglare layer is formed. In the case of ultraviolet curing, a light source such as a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, or a xenon arc can be used. In the case of electron beam curing, electron beams emitted from various electron beam accelerators such as cockloftwald type, bandegraph type, resonant transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type can be used. . The electron beam preferably has an energy of 50 to 1000 KeV. An electron beam having an energy of 100 to 300 KeV is more preferable.

  In addition, you may provide a drying process before and after a hardening process. Moreover, you may perform hardening and drying simultaneously. Examples of the drying means include heating, air blowing, and hot air.

  A case where an antiglare layer is formed using a thermoplastic resin as the binder matrix will be described. The aforementioned coating liquid is applied on the substrate. Thereafter, the coating liquid is dried. Thus, an antiglare layer is formed. Examples of the drying means include heating, air blowing, and hot air.

  The case where an anti-glare layer is formed using an inorganic or organic-inorganic composite matrix as the binder matrix will be described. A method for forming the antiglare layer will be described below. The aforementioned coating liquid is applied on the substrate. Thereafter, the coating liquid is cured by applying external energy such as ultraviolet rays, electron beams, and heat. Thus, an antiglare layer is formed. In addition, you may provide a drying process before and after a hardening process. Moreover, you may perform hardening and drying simultaneously. Examples of the drying means include heating, air blowing, and hot air.

  Moreover, when using the polarizing plate which has a polarizing layer between the support body of a pair of polarizing layer as a base material, an anti-glare light-diffusion member can be created as follows. First, an anti-glare layer is provided on the first polarizing layer support among the pair of polarizing layer supports. The method of providing is the same as the above method.

  Next, a polarizing layer is provided on the side opposite to the side where the antiglare layer is provided of the first polarizing layer support. When the polarizing plate is made of stretched PVA to which a TAC film and iodine are added, the PVA to which iodine is added is bonded to the polarizing layer support while stretching to provide a polarizing layer. Next, a second polarizing layer support is provided on the polarizing layer. Alternatively, a polarizing plate having a polarizing layer may be prepared in advance between a pair of polarizing layer supports, and an antiglare layer may be provided on the one polarizing layer support.

  Again, the antiglare light diffusing member of the present invention may further have an antireflection layer, a water repellent layer, an antifouling layer, and the like. Further, a primer layer, an adhesive layer, or the like may be provided for improving the adhesion between the transparent substrate and the antiglare layer or for improving the adhesion between various layers.

  Again, in the antiglare light diffusing member of the present invention, other functional additives may be added to the binder matrix. However, it is preferable that other functional additives do not affect transparency, light diffusibility, and the like. As functional additives, antistatic agents, ultraviolet absorbers, infrared absorbers, antifouling agents, water repellents, refractive index modifiers, adhesion improvers, curing agents, etc. can be used, thereby preventing the antistatic function Functions other than the anti-glare function such as an ultraviolet absorption function, an infrared absorption function, an antifouling function, and a water repellent function can be provided.

  In addition, the antiglare light diffusing member of the present invention is a functional layer having antireflection performance, antistatic performance, antifouling performance, electromagnetic wave shielding performance, infrared absorption performance, ultraviolet absorption performance, color correction performance, etc., if necessary. In order to improve adhesion between various layers, a primer layer, an adhesive layer, or the like may be provided between the layers.

Examples are shown below.
A method for measuring the refractive index of the binder matrix used in the examples will be described below. A coating solution similar to the above coating solution was prepared. However, the coating liquid does not contain particles. The coating solution was applied, dried and cured by the same method as described above. The refractive index of the layer thus obtained was measured. Using a digital refractometer RX2000 (manufactured by Atago), the refractive index was measured by a photorefractive critical angle detection method. Further, the refractive index of the particles was measured by the Becke line detection method (immersion method). Moreover, the measurement of the average particle diameter of particle | grains was measured using the light-scattering type particle size distribution measuring apparatus (SALD-7000 Shimadzu Corporation make).

<Example 1>
A triacetyl cellulose film (TD-80U, manufactured by Fuji Photo Film Co., Ltd., refractive index 1.49, film thickness 80 μm) was used as the substrate. On this base material, an antiglare light scattering coating solution having the composition shown in Table 1 was applied with a slot die coater. Thereafter, the solvent contained in the coating liquid was evaporated.
Thereafter, the antiglare layer was cured by ultraviolet irradiation of 400 mJ in an atmosphere having an oxygen concentration of 0.03% or less using a high pressure mercury lamp. The dried and cured anti-glare layer had a thickness of 4.8 μm. Thus, the anti-glare light diffusing member sample of Example 1 was produced.

<Example 2>
Using the antiglare light scattering coating liquid having the composition shown in Table 1, an antiglare layer was prepared in the same manner as in Example 1 except for the type of the antiglare light scattering coating liquid. The refractive index of the binder matrix, the refractive index of the particles, and the average particle size of the particles were measured in the same manner as in Example 1. The dried and cured antiglare layer had a thickness of 5.0 μm. Thus, the anti-glare light diffusing member sample of Example 2 was produced.

<Example 3>
Using the antiglare light scattering coating liquid having the composition shown in Table 1, an antiglare layer was prepared in the same manner as in Example 1 except for the type of the antiglare light scattering coating liquid. The refractive index of the binder matrix, the refractive index of the particles, and the average particle size of the particles were measured in the same manner as in Example 1. The dried and cured anti-glare layer had a thickness of 4.8 μm. Thus, the anti-glare light diffusing member sample of Example 3 was produced.

<Example 4>
Using the antiglare light scattering coating liquid having the composition shown in Table 1, an antiglare layer was prepared in the same manner as in Example 1 except for the type of the antiglare light scattering coating liquid. The refractive index of the binder matrix, the refractive index of the particles, and the average particle size of the particles were measured in the same manner as in Example 1. The dried and cured antiglare layer had a thickness of 5.0 μm. Thus, the anti-glare light diffusing member sample of Example 4 was produced.

<Example 5>
Using the antiglare light scattering coating liquid having the composition shown in Table 1, an antiglare layer was prepared in the same manner as in Example 1 except for the type of the antiglare light scattering coating liquid. The refractive index of the binder matrix, the refractive index of the particles, and the average particle size of the particles were measured in the same manner as in Example 1. The dried and cured antiglare layer had a thickness of 5.0 μm. Thus, the anti-glare light diffusing member sample of Example 5 was produced.

<Example 6>
Using the antiglare light scattering coating liquid having the composition shown in Table 1, an antiglare layer was prepared in the same manner as in Example 1 except for the type of the antiglare light scattering coating liquid. The refractive index of the binder matrix, the refractive index of the particles, and the average particle size of the particles were measured in the same manner as in Example 1. The dried and cured antiglare layer had a thickness of 5.2 μm. Thus, the anti-glare light diffusing member sample of Example 6 was produced.

<Evaluation>
The internal haze, surface haze, and pencil hardness of each sample obtained in the examples and comparative examples were measured. The results are shown in Table 2. Table 2 shows the evaluation of external light reflection and contrast.

-Reflection of external light The reflection of a fluorescent lamp was visually evaluated with each sample attached to a black plastic plate. As a result of visual evaluation, a case where the reflection was not conspicuous was indicated by a circle (◯), and a case where the reflection was remarkably recognized was indicated by a cross (×).

・ Haze (surface haze, internal haze)
The haze was measured according to JIS K7105 using a haze meter (NDH2000, Nippon Denshoku). The haze of the antiglare light diffusing member of each sample was defined as the total haze. And the surface of the anti-glare light diffusing layer of the anti-glare film is bonded to the triacetyl cellulose film via the double-sided pressure-sensitive adhesive sheet, and the haze of the double-sided pressure-sensitive adhesive sheet and the triacetyl cellulose film is measured from the obtained haze ( The value obtained by subtracting 0.2% was defined as the internal haze. The surface haze was determined by subtracting the internal haze from the total haze.

Pencil hardness Pencil hardness was measured for each sample according to JIS K5400.

Contrast Using a luminance meter (TOPCOM-BM7) for each sample, the white luminance and black luminance of the antiglare light diffusing layer provided on the display surface were measured in a bright room and a dark room with an illuminance of 200 lux. White luminance is the luminance when the display is displaying white, and black luminance is the luminance when the display is displaying black. White brightness / black brightness was defined as contrast, contrast in a bright room was 200 or more, contrast was 300 or more in a dark room, and the contrast was good. Further, a cross mark (x) indicates that the contrast in the bright room is not less than 200 and the contrast in the dark room does not satisfy 300 or more.

  By changing the content of the particles A and the particles B according to Examples 1 to 4, the surface haze and the internal haze of the antiglare light diffusing member can be easily controlled individually. In particular, in Example 4 in which the content of the particle A with respect to the antiglare layer was 1 to 4.5 wt% and the content of the particle B with respect to the antiglare layer was in the range of 0.5 to 4.0 wt%, the surface haze value 1-7%, the internal haze value was 1-7%, and an antiglare light diffusing member excellent in contrast and antiglare properties could be obtained.

FIG. 1 is a schematic sectional view of an antiglare diffusing member of the present invention. FIG. 2 is a schematic cross-sectional view of another embodiment of the antiglare light diffusing member of the present invention. FIG. 3 is a schematic sectional view of a transmissive liquid crystal display using the antiglare light diffusing member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anti-glare light diffusing member 11 Transparent base material 12 Anti-glare layer 120 Binder matrix 12A Particle A
12B Particle B
h (Average) particle size of _a particle A h (Average) particle size of _b particle b H Average film thickness of antiglare layer 13 Antireflection layer 2 Polarizing plate 21 Transparent substrate 22 Transparent substrate 23 Polarizing layer 3 Liquid crystal cell 4 Polarizing plate 41 Transparent substrate 42 Transparent substrate 43 Polarizing layer 5 Backlight unit 7 Polarizing plate unit

Claims (10)

An antiglare light diffusing member comprising a binder matrix, particles A and particles B on a transparent substrate, and having an antiglare layer having irregularities on the surface,
The difference between the refractive index of the particle A and the refractive index of the binder matrix is 0.02 or less, and the difference between the refractive index of the particle B and the refractive index of the binder matrix is 0.03 to 0.20. The average particle size of the particles A is larger than the average film thickness of the antiglare layer, and the average particle size of the particles B is smaller than the average film thickness of the antiglare layer. Antiglare light diffusing member.   2. The antiglare layer according to claim 1, wherein the average particle diameter of the particles A is larger than the average film thickness of the antiglare layer and smaller than a value obtained by multiplying the average film thickness of the antiglare layer by 1.4. Light diffusing member.   The average particle size of the particles B is smaller than a value obtained by multiplying the average film thickness of the antiglare layer by 0.9 and larger than a value obtained by multiplying the average film thickness of the antiglare layer by 0.2. The antiglare light diffusing member according to claim 1.   The content of the particles A with respect to the antiglare layer is in the range of 1.0 to 4.5 wt%, and the content of the particles B with respect to the antiglare layer is in the range of 0.5 to 4.0 wt%. The anti-glare surname light diffusing member according to claim 1. The antiglare member according to claim 1, wherein the film thickness of the antiglare layer is in the range of 2 to 25 µm. The antiglare diffusing member according to claim 1, wherein the standard deviation of the particle size of the particles A is 40% or less of the average particle size. The antiglare diffusing member according to claim 1, wherein a standard deviation of the particle size of the particles B is 15% or less of the average particle size.   2. The antiglare light diffusing member according to claim 1, wherein the substrate is a triacetyl cellulose film.   The antiglare light diffusing member according to claim 1, wherein the substrate also serves as a polarizing plate.   A transmissive liquid crystal display comprising the antiglare light diffusing member according to claim 1, a polarizing plate, a liquid crystal cell, a polarizing plate, and a backlight unit.

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